There are three major types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form when magma or lava cools and solidifies. Sedimentary rocks form through the accumulation and compression of sediments and organic materials. Metamorphic rocks form from existing rocks that have been altered in form due to heat, pressure, and chemical changes in the Earth's crust. Examples of each rock type are given.
1. KINDS OF ROCKS
By:Janine Luberas,
John Edmon
Bartolome,Kimberly
Sison and Joyce Abner
2. 1.Igneous rocks are one of the
three major rock types and are
basically rocks that solidified
from magma. Magma is the
term for liquid or melted rock
and is usually quite hot. After all,
the term igneous comes from
the Latin word for "of fire". Most
people have seen pictures or
video of magma that flows out of
a volcano. When magma flows
onto the surface of the Earth it is
called lava. When the lava cools
and forms a rock, that rock is
an igneous rock.
4. Sedimentary rock are types
of rock that are formed by
the deposition of material at
the Earth's surface and within
bodies of water. Sedimentation is
the collective name for
processes that
cause mineral and/or organic par
ticles (detritus) to settle and
accumulate or minerals
to precipitate from a solution.
Particles that form a sedimentary
rock by accumulating are
called sediment.
6. Metamorphic rock is the transformation of
an existing rock type, the protolith, in a
process called metamorphism, which
means "change in form". The protolithis
subjected to heat and pressure
(temperatures greater than 150 to 200 °C
and pressures of 1500 bars[1]) causing
profound physical and/or chemical change.
The protolith may be sedimentary
rock, igneous rock or another older
metamorphic rock. Metamorphic rocks
make up a large part of
the Earth's crust and are classified by
texture and
by chemical and mineral assemblage
(metamorphic facies). They may be formed
simply by being deep beneath the Earth's
surface, subjected to high temperatures
and the great pressure of the rock layers
above it.
